Specifications

Parameters, Variables and Commands Ver. 0002 A - 29
12. SERCOS GROUP “N”
NP1 FM (F2200) ReducedActuatedMomentumOfInertiaPercentage
Function: (Parameter not available at this time). It shows the ratio between load inertia and that
of the motor rotor. To calculate this ratio one must consider the mechanical
transmission ratio (gear ratio) between the movement of the load and the rotation of
the motor.
This parameter is A MUST for the internal processing of the acceleration feedforward
in the position loop.
Valid values: 0 .. 1000%
Default values: 0%
NP117 O (S117) ResolutionOfFeedback2
Function: It indicates feedback resolution for the direct feedback at X3.
Units: If it is a linear feedback (a scale), the signal period is given in microns. For Fagor
scales (graduated glass), this resolution is 20 microns. In other words, S117=20
If it is a rotary encoder, this resolution is given in lines per turn.
Valid values: 1..2147483647
Default values: 2048 (2048 lines per turn of the rotary encoder)
NP118 O (S118) ResolutionOfLinearFeedback
Function: It indicates what linear feedback resolution is used as Direct Feedback. If the
feedback signal is modified by an external multiplier, the value of this parameter
must reflect the effect of that multiplier.
Units: If it is a linear scale, the feedback signal period is given in decimicrons. In the case
of Fagor linear glass scales this resolution is 20 microns (S118 = 200). In the case
of Fagor Steel tape scales this resolution is 100 microns (S118 = 1000).
When applying a "x10" multiplying factor to a Fagor glass scale (20 microns), then:
S118 = 20 decimicrons.
Valid values: 1..2147483647
Default values: 2048
NP121.# O (S121.#) InputRevolutions
NP122.# O (S122.#) OutputRevolutions
Function: They define the transmission ratio between the motor shaft and the final axis moving
the machine. For example, if the motor turns 5 times for every 3 turns of the
ballscrew, these parameters should be set as follows:
(S121) = 5
(S122) = 3
Valid values: 1..32767 turns
Default values: 1 turn for both parameters (direct coupling)
Motor
Speed
Motor
Speed
INPUT PULLEY
OUTPUT PULLEY
BALLSCREW
TABLE
Example:
Diameter of the output pulley = 25.75 mm
Diameter of the input pulley = 15.3 mm
NP121 = 2575
NP122 = 1530
Gear ratio =2575/1530 =1.683
Ballscrew pitch = 5 mm
NP123 = 5 milimeters